U.S. patent number 6,080,445 [Application Number 09/040,243] was granted by the patent office on 2000-06-27 for method of forming films over insulating material.
This patent grant is currently assigned to Citizen Watch Co., Ltd.. Invention is credited to Ryota Koike, Yukio Miya, Osamu Sugiyama, Takashi Toida.
United States Patent |
6,080,445 |
Sugiyama , et al. |
June 27, 2000 |
Method of forming films over insulating material
Abstract
A method of forming films over an insulating material is
provided whereby an underlayer film having electric conductivity is
formed on the surface of the insulating material constituting a
base member, and a hard carbon film is formed over the underlayer
film so that the surface electrical resistance value of the hard
carbon film can be controlled so as not to cause the surface
thereof to be charged with static electricity by varying an
electrical resistance value of the underlayer film. In the case
where the underlayer film is formed of a metal film composed of
titanium, chromium, tungsten, or the like, the resistance value
thereof can be changed by varying the thickness of the metal film.
In the case where the underlayer film is formed of a semiconductor
film composed of silicon, germanium, or the like, the resistance
value thereof can be changed by varying the thickness of the
semiconductor film, or the concentration of an impurity added
thereto.
Inventors: |
Sugiyama; Osamu (Tokorozawa,
JP), Miya; Yukio (Tokorozawa, JP), Koike;
Ryota (Tokorozawa, JP), Toida; Takashi
(Tokorozawa, JP) |
Assignee: |
Citizen Watch Co., Ltd. (Tokyo,
JP)
|
Family
ID: |
12461156 |
Appl.
No.: |
09/040,243 |
Filed: |
February 19, 1998 |
Foreign Application Priority Data
|
|
|
|
|
Feb 20, 1997 [JP] |
|
|
9-036128 |
|
Current U.S.
Class: |
427/249.7;
427/122; 427/255.7; 427/404; 427/419.7; 427/902 |
Current CPC
Class: |
C23C
16/0272 (20130101); C23C 16/0281 (20130101); C23C
16/26 (20130101); Y10S 427/103 (20130101) |
Current International
Class: |
C23C
16/26 (20060101); C23C 16/02 (20060101); C23C
016/26 () |
Field of
Search: |
;427/249.7,255.7,902,404,122,249.18,249.19,250,419.7 ;428/408 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: King; Roy V.
Attorney, Agent or Firm: Armstrong, Westerman, Hattori,
McLeland & Naughton
Claims
What is claimed is:
1. A method of forming films over an insulating material comprising
steps of:
forming an underlayer film of a metal, a metal carbide, a metal
nitride or a semiconductor on a surface of the insulating material;
and
forming a diamond-like carbon film over the underlayer film, a
surface electrical resistance value of the diamond-like carbon film
being controlled by varying an electrical resistance value of the
underlayer film.
2. A method of forming films over an insulating material according
to claim 1 wherein a metal film is formed as the underlayer
film.
3. A method of forming films over an insulating material according
to claim 1 wherein a semiconductor film is formed as the underlayer
film.
4. A method of forming films over an insulating material according
to claim 1 wherein a first underlayer film of a metal film is
formed on the surface of the insulating material, and a second
underlayer film of a semiconductor film is formed over the first
underlayer film, the two films constituting the underlayer
film.
5. A method of forming films over an insulating material according
to claim 2 wherein the electrical resistance value of the
underlayer film is varied by changing the thickness of the metal
film.
6. A method of forming films over an insulating material according
to claim 3 wherein the electrical resistance value of the
underlayer film is varied by changing the thickness of the
semiconductor film.
7. A method of forming films over an insulating material according
to claim 3 wherein the electrical resistance value of the
underlayer film is varied by changing a concentration of an
impurity added to the semiconductor film.
8. A method of forming films over an insulating material according
to claim 4 wherein the electrical resistance value of the
underlayer film is varied by changing at least either of a
thickness of the first underlayer film of the metal film or that of
the second underlayer film of the semiconductor film.
9. A method of forming films over an insulating material according
to claim 4 wherein the electrical resistance value of the
underlayer film is varied by changing at least either of a
thickness of the first underlayer film of the metal film or
concentration of an impurity added to the second underlayer film of
the semiconductor film.
10. A method of forming films over an insulating material according
to claim 1 wherein the underlayer film is formed of a metal
selected from the group consisting of titanium, chromium and
tungsten; or a carbide or a nitride of any metal among said
metals.
11. A method of forming films over an insulating material according
to claim 3 wherein the semiconductor film as the underlayer film is
formed of a material selected from the group consisting of silicon,
germanium, and a compound of silicon or germanium.
12. A method of forming films over an insulating material according
to claim 4 wherein the first underlayer film of the metal film is
formed of a
metal selected from the group consisting of titanium, chromium, and
tungsten, while the second underlayer film of the semiconductor
film is formed of either silicon or germanium.
13. A method of forming films over an insulating material according
to claim 1 wherein a first underlayer film of a metal film is
formed on the surface of the insulating material, a second
underlayer film of a metal film having higher electric conductivity
than that of the metal film is formed over the first underlayer
film, and a third underlayer film of a semiconductor film is
further formed over the second underlayer film, the three films
constituting the underlayer film.
14. A method of forming films over an insulating material according
to claim 13 wherein the surface electrical resistance value of the
underlayer film is changed by varying primarily the thickness of
the second underlayer film.
15. A method of forming films over an insulating material according
to claim 13 wherein the first underlayer film is formed of a metal
selected from the group consisting of titanium, chromium, and
tungsten, the second underlayer film is formed of a metal selected
from the group consisting of gold, copper, indium, and aluminum,
and the third underlayer film is formed of either silicon or
germanium.
16. A method of forming films over an insulating material according
to claim 1 wherein the insulating material is composed of either
glass or ceramic.
17. A method of forming films over an insulating material according
to claim 1 wherein the insulating material comprises a jig or tool
for handling semiconductor wafers or chips.
18. A method of forming films over an insulating material according
to claim 1 wherein the insulating material comprises a jig or tool
for handling semiconductor wafers or chips, composed of either
glass or ceramic.
19. A method of forming films over an insulating material according
to claim 18 wherein a metal film is formed as the underlayer film,
the electrical resistance value of the underlayer film being
changed by varying the thickness of the metal film.
20. A method of forming films over an insulating material according
to claim 18 wherein a semiconductor film is formed as the
underlayer film, the electrical resistance value of the underlayer
film being changed by varying the thickness of the semiconductor
film or a concentration of an impurity added thereto.
21. A method of forming films over an insulating material according
to claim 18 wherein a first underlayer film of a metal film is
formed on the surface of a transfer arm comprising the insulating
material, and a second underlayer film of a semiconductor film is
formed over the first underlayer film, the two films constituting
the underlayer film, the electrical resistance value of which is
changed by varying either the thickness of the first underlayer
film of the metal film, or the thickness or a concentration of an
impurity of the second underlayer film of the semiconductor
film.
22. A method of forming films over an insulating material according
to claim 18 wherein a first underlayer film of a metal film is
formed on the surface of a transfer arm comprising the insulating
material, a second underlayer film of a metal film having higher
electric conductivity than that of the metal film is formed over
the first underlayer film, and a third underlayer film of a
semiconductor film is further formed over the second underlayer
film, the three films constituting the underlayer film, the
electrical resistance value of which is changed by varying
primarily the thickness of the second underlayer film.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method of forming films over an
insulating material in order to enhance wear resistance of the
insulating material and further to control a surface electrical
resistance value thereof at a desired value by forming a hard
carbon film on the surface thereof.
2. Description of the Related Art
It has lately become a common practice to form a hard carbon film
as a protective film on the surface of a base member composed of
materials such as metal, glass, ceramic, plastics, or the like, for
enhancement in wear resistance of the surface and improvement in
durability thereof.
A hard carbon film is a hydrogenated amorphous carbon film blackish
in color and having properties similar to those of diamond. It is
therefore called a diamond-like carbon (DLC) film, or an i-carbon
film.
The hard carbon film has excellent characteristics such as high
mechanical hardness, a low friction coefficient, excellent
electrical insulation, high thermal conductivity, and high
corrosion resistance.
Accordingly, coating of decorative articles, medical equipment,
magnetic heads, tools, or the like with the hard carbon film for
significantly enhancing durability thereof has been proposed and
put to practical use.
Further, in a system for manufacturing semiconductor devices such
as LSIs (Large Scale Integrated circuits) and the like, an
insulating material such as ceramic instead of metal is used for
jigs, tools, and the like for handling semiconductor wafers and
chips, such as a transfer arm and the like for transferring
semiconductor wafers and chips so as not to contaminate the
semiconductor wafers and chips, and coating of the surfaces of the
jigs, tools, and the like, composed of the insulating material,
with the hard carbon film has been proposed to enhance wear
resistance of the surfaces thereof.
However, as the hard carbon film has high electric resistivity, the
surface of the base member, if coated with the hard carbon film,
comes to have a very high surface electrical resistance value.
As a result, the surfaces of the jigs, tools, and the like are
prone to generate static electricity upon contact with other
members of the manufacturing system, thereby creating a problem in
that the surfaces are prone to attract contaminants and dust in the
atmosphere.
Further, in the case of the hard carbon film being formed over the
surface of the transfer arm for transferring semiconductor wafers
and chips, and the like, the following problem will arise in
addition to the problem of contaminants and dust adhering to the
surface due to the effect of static electricity.
For example, in the case where semiconductor wafers and chips
provided with a multitude of semiconductor integrated circuit
elements integrated thereon are handled, electrostatic destruction
of a gate insulation film of, for example, a MOS transistor, caused
by static electricity with which the surfaces of jigs, tools, and
the like handling semiconductor wafers and chips are charged will
pose a serious problem because the gate insulation film is very
thin due to advanced integration of the semiconductor integrated
circuit.
FIG. 13 is a graph showing an example of measurement results with
reference to surface electrical resistance values of a hard carbon
film, wherein the abscissa indicates the thickness of the hard
carbon film and the ordinate indicates resistance between
terminals, that is, surface electrical resistance values.
As samples used for measuring the surface electrical resistance
value of the hard carbon film, five types of samples with a hard
carbon film 0.1 .mu.m, 0.4 .mu.m, 0.8 .mu.m, 1.2 .mu.m, and 1.5
.mu.m thick, respectively, formed on respective borosilicate glass
plates 1.1 mm thick were prepared. Measurement results thereof are
plotted as shown by a curve 36.
Now, a method of measuring the surface electrical resistance value
is described with reference to FIG. 14. As shown in FIG. 14, a pair
of measurement terminals 22a, 22b, disposed at a predetermined
spacing (1 mm), are brought into contact with the surface of each
sample provided with a hard carbon film 16 formed on the respective
borosilicate glass plates, which is a base member 12.
Then, a DC power source 18 and an ammeter 20 are connected to the
measurement terminals 22a, 22b in series. A DC voltage at 50 V
supplied from the DC power source 18 is applied between the
measurement terminals 22a and 22b, and the amperage of current
flowing through the measurement terminals 22a, 22b is measured by
means of the ammeter 20, finding the surface electrical resistance
value of the hard carbon film 16 by calculation.
As shown by the curve 36 of the graph in FIG. 13, the surface
electrical resistance value of the hard carbon film 16 is on the
order of 10.sup.11 .OMEGA.. Further, it has been found that the
thicker the thickness of the hard carbon film 16, the smaller the
surface electrical resistance value becomes. This is presumably
attributable to an increase in amperage of current flowing through
the hard carbon film as the thickness thereof increases.
Thus, the surface electrical resistance value of the hard carbon
film formed on the surfaces of the jigs, tools, and the like
composed of the insulating material is as high as on the order of
10.sup.11 .OMEGA.. Hence, there is a risk of the surfaces thereof,
charged with static electricity, attracting contaminants and dust,
or causing electrostatic destruction to occur due to the static
electricity when semiconductor wafers and chips are handled.
Therefore, the merits of the hard carbon film can not be fully
utilized, and consequently, jigs, tools, and, the like, provided
with the hard carbon film for use in handling semiconductor wafers
and chips, the surfaces of which are not charged with static
electricity, are in great demand.
Accordingly, as disclosed in, for example, Japanese Patent
Laid-open Publication No. 2-30761, and the like, a proposal has
been made wherein electric conductivity of a hard carbon film is
controlled by causing a halogen, or hydrogen and halogen, to be
contained in the hard carbon film formed on the surface of a base
member made of a metal or an insulating material such that the
concentration of the halogen is distributed depthwise in the hard
carbon film deposited on the surface of the base member.
That is, when forming the hard carbon film by means of the plasma
CVD method, a halogen such as F, Cl, Br, I, or the like is added by
supplying to a plasma a fluoride such as NF.sub.3, SF.sub.4,
WF.sub.6, or the like, a chloride such as CCl.sub.4, or the like, a
bromide such as CH.sub.3 Br, or an iodide, as feed material for the
halogen.
By forcing a halogen to be contained in the hard carbon film as
described above, it is possible to improve electric conductivity of
the hard carbon film, and to lower the surface electrical
resistance value thereof. However, another problem will ensue from
this in that the characteristics of the hard carbon film such as
hardness and the like are deteriorated, and the merits thereof such
as enhanced wear resistance is impaired.
Further, another proposal has also been made wherein a film
composed of a
metal such as W, Ni, or the like is formed by, for example, the
sputtering process, during the formation of the hard carbon film,
forming the hard carbon film containing metal particles so that the
surface electrical resistance value is lowered.
With this method, however, since the metal particles are mixed into
the hard carbon film, it is unavoidable that the characteristics
thereof such as hardness and the like are deteriorated, and the
beneficial effects such as enhanced wear resistance are impaired.
Furthermore, in this case, process control during a process of
forming films as well as accurate control of the surface electrical
resistance value is difficult to achieve.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a method of
forming films over an insulating material whereby a hard carbon
film is formed on the surface of the insulating material such that
a surface electrical resistance value of the hard carbon film can
be controlled in such a way as not to cause the surface thereof to
be charged with static electricity without impairing the hardness
thereof, solving all the problems described in the foregoing.
To this end, the method of forming films over the insulating
material according to the invention comprises the steps of forming
an underlayer film having high electric conductivity on the surface
of the insulating material such as glass, ceramic, and the like,
and forming the hard carbon film over the underlayer film, a
surface electrical resistance value of the hard carbon film being
controlled by varying an electrical resistance value of the
underlayer film.
A metal film or a semiconductor film may be formed as the
underlayer film. In the case of a metal film being used, the
electrical resistance value of the underlayer film can be changed
by varying the thickness of the metal film or type of the metal
therefor. In the case a the semiconductor film being used, the
electrical resistance value of the underlayer film can be changed
by varying the thickness of the semiconductor film, type of the
semiconductor therefor, or concentration of an impurity
(dopant).
Also, a first underlayer film of a metal film may be formed on the
surface of the insulating material, and a second underlayer film of
a semiconductor film may be formed over the first underlayer film,
the two films constituting the underlayer film.
In such a case, the electrical resistance value of the underlayer
film can be changed by varying either the thickness of the first
underlayer film of the metal film, or the thickness or the
concentration of an impurity of the second underlayer film of the
semiconductor film.
The metal film as the underlayer film may be formed of a metal
selected from the group consisting of titanium, chromium, tungsten,
or a carbide and nitride of one of said metals. Further, the
semiconductor film as the underlayer film may be formed of a
material selected from the group consisting of silicon, germanium,
or a compound of silicon or germanium.
It is more preferable to form a first underlayer film of a metal
film on the surface of the insulating material, a second underlayer
film of a metal film having higher electric conductivity than that
of the metal film over the first underlayer film, and furthermore,
a third underlayer film of a semiconductor film over the second
underlayer film, the three films constituting the underlayer film
formed between the insulating material and the hard carbon
film.
In this case, the surface electrical resistance value of the
underlayer film can be changed primarily by varying the thickness
of the second underlayer film.
Further, the first underlayer film may be formed of a metal
selected from the group consisting of titanium, chromium, and
tungsten, the second underlayer film may be formed of a metal
selected from the group consisting of gold, copper, indium, and
aluminum, and the third underlayer film may be formed of either of
silicon and germanium.
By forming the hard carbon film on the surface of a jig or tool
such as a transfer arm for handling semiconductor wafers or chips
with the use of the method of the invention, wear resistance of the
surface of the jig or tool, composed of an insulating material such
as ceramic, is considerably enhanced, and generation of dust caused
by abrasion of the surface can be prevented while the surface
electrical resistance value is lowered, keeping the surface from
being charged with static electricity, and preventing adsorption of
dust to the semiconductor wafers or chips being handled, and
occurrence of electrostatic destruction.
The above and other objects, features and advantages of the
invention will be apparent from the following detailed description
which is to be read in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view illustrating the construction
of films formed over an insulating material by the first embodiment
according to the invention.
FIG. 2 is a graph showing an example of measurement of surface
electrical resistance values and thickness of hard carbon films
formed according to the first embodiment.
FIG. 3 is a schematic sectional view illustrating the construction
of films formed over an insulating material by the second
embodiment according to the invention.
FIG. 4 is a graph showing an example of measurement of surface
electrical resistance values and thickness of hard carbon films
formed according to the second embodiment.
FIG. 5 is a schematic sectional view illustrating the construction
of films formed over an insulating material by the third embodiment
according to the invention.
FIG. 6 is a graph showing an example of measurement of surface
electrical resistance values and thickness of hard carbon films
formed according to the third embodiment.
FIG. 7 is a schematic sectional view of a sputtering system for
forming a single-layer underlayer film on the surface of an
insulating material according to the method of the invention.
FIG. 8 is a schematic sectional view of a plasma CVD system for
forming a hard carbon film over the insulating material with the
underlayer film formed thereon, according to the method of the
invention.
FIG. 9 is a schematic sectional view of a sputtering system for
forming double-layer underlayer film on the surface of the
insulating material according to the method of the invention.
FIG. 10 is a schematic sectional view of a sputtering system for
forming triple-layer underlayer film on the surface of the
insulating material according to the method of the invention.
FIG. 11 is a plan view illustrating a state in which a
semiconductor wafer is mounted on a transfer arm for semiconductor
wafers to which the method of the invention is applied, and
FIG. 12 is a side view thereof.
FIG. 13 is a graph showing an example of measurement of surface
electrical resistance values of a hard carbon film formed on the
surface of an insulating material according to the conventional
method.
FIG. 14 is a view illustrating a method of measuring surface
electrical resistance values of a hard carbon film.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of a method of forming films over an
insulating material according to the invention will be described in
detail hereinafter with reference to the accompanying drawings.
First Embodiment: FIGS. 1 and 2
FIG. 1 is a schematic sectional view illustrating the construction
of films formed over an insulating material by a first embodiment
of a method according to the invention.
In the construction shown in FIG. 1, a hard carbon film 16 is
provided via an underlayer film 14 formed over an insulating
material 12 comprising a base member of various components, jigs,
tools, or the like. The insulating material 12 is glass, ceramic,
resin (plastics), or the like.
A metal film or semiconductor film as the underlayer film 14 is
formed on the surface of the insulating material 12. The underlayer
film 14 is formed by means of a physical vapor deposition method,
such as the sputtering method, vacuum deposition method or the
like, or the CVD (chemical vapor deposition) method.
Then, the hard carbon film 16 is formed over the underlayer film
14. The hard carbon film 16 is formed by means of the plasma CVD
method using methane (CH.sub.4) as feed gas.
In the case of a metal film being used for the underlayer film 14,
titanium (Ti), chromium (Cr), tungsten (W), or the like may be used
to form the metal film. Further, a compound such as a carbide,
nitride, or the like of one of these metals can also be used for
the underlayer film 14.
In the case of a semiconductor film being used for the underlayer
film 14, silicon (Si) or germanium (Ge) may be used. Further, a
compound of silicon or germanium may also be used for the
underlayer film 14.
The surface electrical resistance value of the hard carbon film 16
can be controlled by varying the electrical resistance value of the
underlayer film 14.
In the case of the underlayer film 14 being a metal film, the
electrical resistance value thereof can be varied by changing the
kind of a metal used, chemical composition of a compound such as a
carbide, nitride, or the like of the metal, or the thickness of the
metal film used.
In the case of the underlayer film 14 being a semiconductor film,
the electrical resistance value thereof can be varied by changing
the type of semiconductor used, the thickness of the semiconductor
film used, or the concentration of an impurity introduced into the
semiconductor film. Phosphorus (P), boron (B), and arsenic (As) are
among the impurities that may be introduced into the semiconductor
film.
The impurities are introduced in the semiconductor film
concurrently during the formation of the semiconductor film. For
example, in the case where phosphorus is introduced into a silicon
film through the CVD process, monosilane (SiH.sub.4) as feed gas
for silicon, and phosphine (PH.sub.3), are fed into a CVD
chamber.
The surface electrical resistance value of the hard carbon film 16
covering the insulating material 12 in this way can be reduced to a
desired value at which the surface of the hard carbon film 16 will
not become charged with static electricity.
A specific example of the first embodiment of the invention is
described with reference to the graph in FIG. 2.
The graph shown in FIG. 2 indicates surface electrical resistance
values of the hard carbon film 16 when the same is formed over the
upper surface of a n-type silicon film (semiconductor film) formed,
as the underlayer film 14, on the surface of the insulating
material 12 shown in FIG. 1, for which glass is used.
Three types of samples provided with a hard carbon film 0.4 .mu.m,
1.1 .mu.m, and 1.9 .mu.m thick, respectively, were prepared, and
electrical resistance values of the respective samples between the
measurement terminals were measured, plotting the measurement
results in FIG. 2. That is, the abscissa indicates thickness of the
hard carbon film and the ordinate thereof indicates resistance
between terminals, that is, the surface electrical resistance
values, in FIG. 2.
The curve 26 indicates the case of a silicon film, as an underlayer
film, having specific resistance in the range of 1 to 5 .OMEGA./m
(in this case, the concentration of the impurity was from
9.times.10.sup.14 to 5.times.10.sup.15 atoms/cm.sup.3) while the
curve 24 indicates a case of a silicon film having specific
resistance in the range of 10 to 20 .OMEGA./cm (in this case, the
concentration of the impurity was from 2.5.times.10.sup.14 to
5.times.10.sup.14 atoms/cm.sup.3).
More specifically, the hard carbon film was formed on the silicon
films having differing specific resistances, respectively, and the
surface electrical resistance values of the hard carbon film in
respective cases were measured. The method of measuring the surface
electrical resistance value was the same as previously described
with reference to FIG. 14. The results of measurement shown in FIG.
2, however, were obtained by applying a DC voltage at 10 V supplied
from the DC power source 18 in FIG. 14.
As is evident from the curves 24 and 26 shown in FIG. 2, the
surface electrical resistance value of the hard carbon film can be
controlled by varying the specific resistance of the silicon film,
that is, the underlayer film underneath the hard carbon film. It
has been found from comparison of the curve 26 for the case of the
silicon film having a specific resistance in the range of 1 to 5
.OMEGA./cm with the curve 24 for the case of the silicon film
having a specific resistance in the range of 10 to 20 .OMEGA./cm
that the surface electrical resistance value of the hard carbon
film 1.1 .mu.m thick was 9.times.10.sup.6 .OMEGA., and
4.times.10.sup.6 .OMEGA., respectively.
This shows therefore that the surface electrical resistance value
of the hard carbon film can be controlled by varying the electrical
resistance value of the underlayer film. Further, the surface
electrical resistance value of the hard carbon film in this case
was found to be on the order of 10.sup.6 .OMEGA., significantly
lower than the surface electrical resistance value (on the order of
10.sup.11 .OMEGA.) of the conventional hard carbon film shown in
FIG. 13.
Second Embodiment: FIGS. 3 and 4
Next, a second embodiment according to the invention will be
described hereinafter. FIG. 3 is a schematic sectional view
illustrating the construction of the films formed over an
insulating material.
In the construction shown in FIG. 3, a hard carbon film 16 is
provided via a first underlayer film 14a and second underlayer film
14b formed over an insulating material 12 comprising a base member
of various components, jigs, tools, or the like. The insulating
material 12 is glass, ceramic, resin (plastics), or the like.
For the first underlayer film 14a, a metal film composed of a metal
selected from the group consisting of titanium (Ti), chromium (Cr),
tungsten (W), or a compound such as a carbide, nitride, or the like
of one of the aforesaid metals is formed on the surface of the
insulating material 12.
For the second underlayer film 14b, a semiconductor film composed
of silicon (Si), germanium (Ge), or the like is formed over the
first underlayer film 14a.
The underlayer films 14a, 14b are formed by means of a physical
vapor deposition method such as the sputtering method, vacuum
deposition method or the like, or the CVD (chemical vapor
deposition) method as previously described with reference to the
first embodiment of the invention.
With the construction of the films shown in FIG. 3, the surface
electrical resistance value of the hard carbon film can be
controlled by varying the electrical resistance value of either or
both of the first underlayer film 14a and the second underlayer
film 14b.
The electrical resistance value of the first underlayer film 14a
can be varied by changing the kind of metal constituting the metal
film, chemical composition of the carbide, nitride, or other
compound of the metal, or the thickness of the metal film.
The electrical resistance value of the second underlayer film 14b
can be varied by changing the type of semiconductor constituting
the semiconductor film, the thickness of the semiconductor film, or
the concentration of the impurity added to the semiconductor
film.
The surface electrical resistance value of the hard carbon film 16
covering the insulating material 12 in this way can be reduced with
greater ease to a required value at which the surface of the hard
carbon film 16 will not be charged with static electricity.
A specific example of the second embodiment of the invention is
described with reference to a graph in FIG. 4.
The graph shown in FIG. 4 indicates electrical resistance between
the measurement terminals, that is, surface electrical resistance
values of the hard carbon film 16, with the construction of the
films being as shown
in FIG. 3, wherein glass is used for an insulating material 12
constituting a base member, a titanium film as a first underlayer
film 14a is formed on the surface of the insulating material 12,
and a silicon film is formed as a second underlayer film 14b over
the first underlayer film 14a, forming the hard carbon film 16 over
the upper surface of the second underlayer film 14b.
Three types of samples provided with a hard carbon film 0.5 .mu.m,
0.9 .mu.m, and 1.2 .mu.m thick, respectively, were prepared, and
electrical resistance values of the respective samples between the
measurement terminals were measured, plotting the measurement
results in FIG. 4.
In this instance, only the thickness of the titanium film, that is,
the first underlayer film 14a, was varied, keeping the thickness of
the silicon film, that is, the second underlayer film 14b, constant
(at 0.1 .mu.m).
The curve 28 represents the case of the titanium film being 0.4
.mu.m thick, wherein the electrical resistance values of the hard
carbon film between the measurement terminals were
2.7.times.10.sup.5 .OMEGA., 3.2.times.10.sup.5 .OMEGA., and
9.times.10.sup.5 .OMEGA. for the thickness thereof at 0.5 .mu.m,
0.9 .mu.m, and 1.2 .mu.m, respectively.
The curve 30 represents the case of the titanium film being 0.1
.mu.m thick, wherein the electrical resistance values of the hard
carbon film between the measurement terminals were
4.7.times.10.sup.5 .OMEGA., 5.2.times.10.sup.5 .OMEGA., and
1.7.times.10.sup.6 .OMEGA. for the thickness thereof at 0.5 .mu.m,
0.9 .mu.m, and 1.2 .mu.m, respectively.
In this case, phosphorus was introduced as an impurity into the
silicon film which is the second underlayer film 14b. That is, the
silicon film which is the second underlayer film 14b was formed by
means of the DC sputtering method wherein an n-type silicon
material containing phosphorus was used as the target material. As
the specific resistance of the n-type silicon material as the
target material was around 100 .OMEGA./cm, the second underlayer
film 14b had substantially the same specific resistance as that of
the silicon material.
The method of measuring the surface electrical resistance value
(resistance between the measurement terminals) of the hard carbon
film in this case was the same as previously described with
reference to FIG. 14. The results of measurement shown in FIG. 4,
however, were obtained by applying a DC voltage at 10 V supplied
from the DC power source 18 in FIG. 14.
As is evident from the curves 28 and 30 shown in FIG. 4, the
surface electrical resistance value of the hard carbon film can be
controlled by varying the thickness of the first underlayer film,
that is, an electrical resistance value of the film.
More specifically, it has been found from comparison of the curve
28 for the case of the titanium film, that is, the first underlayer
film, being 0.4 .mu.m thick, with the curve 30 for the case of the
same being 0.1 .mu.m thick, that the surface electrical resistance
value of the hard carbon film 0.9 .mu.m thick was
3.2.times.10.sup.5 .OMEGA. and 5.2.times.10.sup.5 .OMEGA.,
respectively.
The values described above are further lower than the surface
electrical resistance values of the hard carbon film in the case of
the first embodiment as indicated in FIG. 2.
In this embodiment, only the thickness, that is, the electrical
resistance value of the titanium film (metal film) which is the
first underlayer film 14a, was varied. However, the inventors have
confirmed that the same results can also be attained by varying the
electrical resistance value of the silicon film (semiconductor
film), that is, the second underlayer film 14b. Further, in this
case, the electrical resistance value of the silicon film can be
varied by changing the thickness thereof, or the concentration of
the impurity added thereto.
Still further, the electrical resistance values of both the metal
film as the first underlayer film 14a, and the semiconductor film
as the second underlayer film 14b may also be varied.
For the insulating material 12, ceramic, plastics, or the like
besides glass may alternatively be used.
Third Embodiment: FIGS. 5 and 6
Next, the third embodiment according to the invention will be
described hereinafter. FIG. 5 is a schematic sectional view
illustrating the construction of the films formed over an
insulating material.
In the construction shown in FIG. 5, a hard carbon film 16 is
provided via a first underlayer film 14a, second underlayer film
14c, and third underlayer film 14d, formed over an insulating
material 12 comprising a base member of various components, jigs,
tools, or the like. The insulating material 12 is glass, ceramic,
resin (plastics), or the like.
For the first underlayer film 14a, a metal film composed of a metal
selected from the group consisting of titanium (Ti), chromium (Cr),
tungsten (W), or a compound such as a carbide, nitride, or the
like, of one of the aforesaid metals is formed to a thickness in
the range of 0.1 to 0.2 .mu.m on the surface of the insulating
material 12.
For the second underlayer film 14c, a metal film composed of a
metal selected from the group consisting of gold (Au), copper (Cu),
indium (In), aluminum (Al), or the like, having higher electric
conductivity than the first underlayer film 14a, is formed to a
thickness in the range of 0.5 to 1.0 .mu.m over the first
underlayer film 14a.
For the third underlayer film 14d, a semiconductor film composed of
silicon, germanium, or the like is formed to a thickness in the
range of 0.1 to 0.2 .mu.m over the second underlayer film 14c.
The underlayer films 14a, 14c, and 14d are formed by means of a
physical vapor deposition method such as the sputtering method,
vacuum deposition method or the like, or the CVD (chemical vapor
deposition) method as previously described with reference to the
embodiments described hereinbefore.
This embodiment is characterized by having a metal film having high
electric conductivity (low specific resistance), as the second
underlayer film 14c, interposed between the underlayers, to allow
electric current in large amounts to flow therethrough so that the
surface electrical resistance value of the hard carbon film 16 can
be lowered with ease due to a decrease in the electrical resistance
value of the underlayers as a whole.
The first underlayer film 14a, composed of titanium, chromium, or
the like, is necessary to enhance adhesion with the insulating
material 12 constituting the base member, and the third underlayer
film 14d, composed of silicon, germanium, or the like, is necessary
to enhance adhesion with the hard carbon film 16.
A specific example of the third embodiment of the invention will be
described with reference to a graph in FIG. 6.
The graph shown in FIG. 6 indicates resistance between the
measurement terminals, that is, surface electrical resistance
values of the hard carbon film 16, with the construction of the
films being as shown in FIG. 5, wherein glass is used for the
insulating material 12 constituting the base member, a titanium
(Ti) film as the first underlayer film 14a, a copper (Cu) film as
the second underlayer film 14c, and a silicon (Si) film as the
third underlayer film 14d are formed, respectively, on the surface
of the insulating material 12, the hard carbon film 16 being formed
over the upper surface of the third underlayer film 14d.
Three types of samples provided with a hard carbon film 0.5 .mu.m,
0.9 .mu.m, and 1.2 .mu.m thick, respectively, were prepared, and
electrical resistance values of the respective samples between the
measurement terminals were measured, the measurement results being
plotted in FIG. 6.
In this instance, only the thickness of the copper film, that is,
the second underlayer film 14c, was varied, keeping the thickness
of both the Ti film, that is, the first underlayer film 14a and the
Si film, that is, the third underlayer film 14d, constant (at 0.1
.mu.m).
The curve 32 represents the case of the Cu film being 0.6 .mu.m
thick, wherein electrical resistance values of the hard carbon film
between the measurement terminals were 8.0.times.10.sup.4 .OMEGA.,
9.0.times.10.sup.4 .OMEGA., and 2.2.times.10.sup.5 .OMEGA. for the
thickness thereof at 0.5 .mu.m, 0.9 .mu.m, and 1.2 .mu.m,
respectively.
The curve 34 represents the case of the Cu film being 0.3 .mu.m
thick, wherein electrical resistance values of the hard carbon film
between the measurement terminals were 2.0.times.10.sup.5 .OMEGA.,
2.4.times.10.sup.5 .OMEGA., and 6.8.times.10.sup.5 .OMEGA. for the
thickness thereof at 0.5 .mu.m, 0.9 .mu.m, and 1.2 .mu.m,
respectively.
As is evident from the curves 32 and 34 of the graph shown in FIG.
6, the surface electrical resistance value of the hard carbon film
can be controlled with ease by varying the thickness of the second
underlayer film 14c, one of the underlayer films, that is, the
electrical value of the film.
More specifically, it has been found from comparison of the curve
32 for the case of the Cu film, that is, the second underlayer
film, being 0.6 .mu.m thick, with the curve 34 for the case of the
same being 0.3 .mu.m thick, that the surface electrical resistance
value of the hard carbon film 0.9 .mu.m thick was 9.times.10.sup.4
.OMEGA., and 2.4.times.10.sup.5 .OMEGA., respectively. These values
show that the surface electrical resistance values (resistance
between the measurement terminals) of the hard carbon film
according to this embodiment are further lower than the measurement
results in the case of the double-layer underlayer films as
indicated in FIG. 4.
In this embodiment, the electrical resistance value of the
underlayer films is varied by changing primarily the thickness of
the second underlayer film 14c so as to control the surface
electrical resistance value of the hard carbon film 16. However,
the electrical resistance value of the first underlayer film 14a or
that of the third underlayer film 14d may alternatively be
varied.
The surface electrical resistance value of the hard carbon film 16
formed as described above over the insulating material 12 will be
affected by the underlayer films formed in layers thereunder
because the thickness of the hard carbon film 16 is as thin as 2
.mu.m or less. More specifically, the electric current flowing
through the surface of the hard carbon film 16, that is, between
the measurement terminals 22a and 22b shown in FIG. 14, is a
composite of the electric current flowing through the hard carbon
film 16 and the same flowing through the underlayer films after
penetrating through the hard carbon film 16.
Accordingly, the current flowing through the underlayer films can
be increased by rendering resistance in the underlayer films lower
than that in the hard carbon film with the result that the surface
electrical resistance value of the hard carbon film can be reduced.
It follows that the surface electrical resistance value of the hard
carbon film can be controlled by varying the resistance value of
the underlayer films formed in layers underneath the hard carbon
film.
It has been found on the basis of results of experiments that the
surface electrical resistance value of the hard carbon film bearing
the least electrical charge in the surface thereof was around
10.sup.5 .OMEGA.. Accordingly, the electrical resistance value of
the underlayer may be controlled such that the surface electrical
resistance value of the hard carbon film will be on the order of
that number.
System for Use in Carrying Out the Invention: FIGS. 7 to 10
Now, a system for use in carrying out the method of forming films
over an insulating material according to the invention will be
described hereinafter.
A system for use in carrying out the method of forming films
according to the first embodiment of the invention, as illustrated
in FIG. 1, will first be described with reference to FIGS. 7 and
8.
FIG. 7 is a schematic sectional view of a sputtering system for
forming a single-layer underlayer film on the surface of an
insulating material. The sputtering system is constructed such that
a ground cover 41 is fixedly mounted on the inside of a vacuum
chamber, an n-type silicon material 42 as a target material for
forming the underlayer film is securely held by the ground cover 41
via an insulating member (not shown), and an insulating material 12
for constituting a base member is disposed so as to face the n-type
silicon material 42.
The vacuum chamber 40 is evacuated by an evacuating means (not
shown) through an air outlet 40a to a degree of vacuum on the order
of 3.times.10.sup.-5 torr. Thereafter, argon gas as a sputtering
gas is fed into the vacuum chamber 40 through a gas inlet 40b,
adjusting the degree of vacuum to reach a level on the order of
1.times.10.sup.-3 torr.
At this point in time, both the vacuum chamber 40 and the ground
cover 41 are grounded, and with a switch S1 closed, a DC voltage of
-600 V supplied from a DC power source 43 is applied to the silicon
material 42, thereby causing a plasma to occur in the vacuum
chamber 40. The surface of the silicon material 42 is then
sputtered by argon ions in the plasma.
Silicon (Si) molecules ejected by the sputtering process described
above are deposited on the surface of the insulating material 12.
By applying the sputtering process for about 30 minutes, a silicon
film as the underlayer film 14 shown in FIG. 1 can be formed to a
thickness on the order of 0.5 .mu.m.
The thickness of the silicon film can optionally be adjusted by
selecting the length of processing time, thereby varying the
electrical resistance value of the silicon film as the underlayer
film. Further, it is possible to change the electrical resistance
value of the silicon film to be formed by varying the concentration
of an impurity (phosphorus, boron, arsenic, or the like) contained
in the silicon material 42 for use as the target material.
In the case of forming a germanium film, that is, another
semiconductor film, a metal film such as a titanium film, chromium
film, tungsten film, or a film composed of a carbide or a nitride
of one of these metals, such films can be formed similarly with the
use of the sputtering system described in the foregoing by simply
changing the target material to be held by the ground cover 41 to a
material for the respective film type.
FIG. 8 is a schematic sectional view of a plasma CVD system for
forming a hard carbon film over the insulating material with the
underlayer film formed thereon as described above.
In the system, a vacuum chamber 50 having an air outlet 50a and a
gas inlet 50b is provided with an anode 51 and a filament 52 in the
upper part thereof. The insulating material 120 with the underlayer
film formed thereon is disposed inside the vacuum chamber 50,
opposite to the anode 51.
Then, the vacuum chamber 50 is evacuated through the air outlet 50a
until the degree of vacuum reaches a level on the order of
3.times.10.sup.-5 torr. Thereafter, benzene (C.sub.6 H.sub.6) as a
carbon-containing gas is fed into the vacuum chamber 50 through the
gas inlet 50b, adjusting pressure inside the vacuum chamber 50 to
reach a level on the order of 1.times.10.sup.-3 torr.
The vacuum chamber 50 is then grounded, and a DC voltage of -3 kV
supplied from a DC power source 53 is applied to the underlayer
film (the silicon film in the case of the example described
hereinbefore) of the insulating material 120 while a DC voltage of
+50 V supplied from an anode power source 54 is applied to the
anode 51 in the vacuum chamber 50, and an AC voltage of 10 V
supplied from a filament power source 55 is applied to the filament
52 to cause electric current of 30A to flow therethrough.
As a result, a plasma is caused to occur in a region surrounding
the insulating material 120 inside the vacuum chamber 50, and
through the plasma CVD process, the hard carbon film composed of
hydrogenated amorphous carbon is formed over the underlayer film of
the insulating material 120. The thickness thereof can be
optionally adjusted by selecting the length of processing time.
As the plasma CVD process whereby the hard carbon film is formed on
the surface of the insulating material 120 with the underlayer
films formed thereon, there are other methods available such as a
method wherein a vacuum chamber not provided with an anode and
filament is employed, causing a plasma to occur by applying RF
power to the underlayer film of the insulating material 120
disposed inside the vacuum chamber, and a method wherein a plasma
is caused to occur simply by applying a DC voltage
to the underlayer film of the insulating material 120.
Now, a system for use in carrying out the method of forming the
films according to the second embodiment of the invention, as
illustrated in FIG. 3, will be described hereinafter with reference
to FIG. 9.
FIG. 9 is a schematic sectional view of a sputtering system for
forming double-layer underlayer film on the surface of an
insulating material.
In the system, two ground covers 41a, 41b are disposed inside a
vacuum chamber 40, spaced apart from each other. A titanium
material 44 for forming the first underlayer film is securely held
as a target material by the first ground cover 41a via an
insulating member (not shown) while an n-type silicon material 42
for forming the second underlayer film is securely held as a target
material by the second ground cover 41b via an insulating member
(not shown).
Then, an insulating material 12 for constituting a base member is
disposed so as to face the titanium material 44 as shown by the
solid lines in FIG. 9. After the vacuum chamber 40 is grounded and
evacuated to a preset degree of vacuum in the same way as
previously described, argon gas as a sputtering gas is fed therein,
a switch S1 is closed, and a DC voltage on the order of -600 V
supplied from a DC power source 43a is applied to the titanium
material 44.
As a result, a plasma is caused to occur in a region surrounding
the titanium material 44 inside the vacuum chamber 40, and the
surface of the titanium material 44 is sputtered by argon ions in
the plasma.
Titanium (Ti) molecules ejected by sputtering are deposited on the
surface of the insulating material 12, forming a titanium film as
the first underlayer film 14a shown in FIG. 3. The thickness
thereof can be optionally adjusted by selecting the length of
processing time.
Subsequently, the switch S1 is opened, and a switch S2 is closed
after transferring the insulating material 12 with the first
underlayer film 14a formed thereon to a position opposite the
silicon material 42 as the target material as shown by the
imaginary lines in FIG. 9, and applying a DC voltage around -600 V
supplied from a DC power source 43b to the silicon material 42.
Then, in the same way as in the preceding step, the sputtering
process is applied to the silicon material 42, forming a silicon
film as the second underlayer film 14b over the first underlayer
film 14a covering the insulating material 12, as shown in FIG. 3.
The thickness thereof can be optionally adjusted by selecting the
length of processing time, and the electrical resistance value of
the silicon film to be formed can also be controlled according to
the concentration of impurity contained therein by varying the
concentration of the impurity added to the silicon material 42 used
as the target material.
In the case of employing another metal film for the first
underlayer film, or another semiconductor film for the second
underlayer film, these films can be similarly formed simply by
changing respective target materials.
In the example shown in FIG. 9, the DC power sources 43a, 43b are
separately installed so that voltages applied to the titanium
material 44 and the silicon material 42, respectively, can be
optimized. However, a common DC power source may be adopted
instead. In this case, the DC power source preferably should be
designed so as to be able to regulate an output voltage as
necessary.
The method of forming the hard carbon film 16 over the second
underlayer film 14b after the first and second underlayer films
14a, 14b are formed on the surface of the insulating material 12 as
shown in FIG. 3 is the plasma CVD process employing the same system
as described in the case of the embodiment previously described
with reference to FIG. 8, and explanation thereof is therefore
omitted.
Now, a system for use in carrying out the method of forming the
films according to the third embodiment of the invention, as
illustrated in FIG. 5, will be described hereinafter with reference
to FIG. 10.
FIG. 10 is a schematic sectional view of a sputtering system for
forming triple-layer underlayer film on the surface of an
insulating material. In the system, three ground covers 41a, 41b,
41c are disposed inside a vacuum chamber 40, spaced apart from each
other.
A titanium material 44 as a target material for forming a first
underlayer film is securely held by a first ground cover 41a via an
insulating member (not shown), a copper material 45 as a target
material for forming a second underlayer film is securely held by a
second ground cover 41b via an insulating member, and an n-type
silicon material 42 as a target material for forming a third
underlayer film is securely held by a third ground cover 41c via an
insulating member.
Then, an insulating material 12 for constituting a base member is
first disposed so as to face the titanium material 44 as shown by
the solid lines in FIG. 10. After evacuating the vacuum chamber 40,
already grounded, to a degree of vacuum in the same way as
previously described, argon gas as a sputtering gas is fed therein,
a switch S1 is closed, and a DC voltage on the order of -600 V
supplied from a DC power source 43a is applied to the titanium
material 44.
Thus, the sputtering process is applied to the titanium material 44
in the same way as in the preceding step, and a titanium film as
the first underlayer film 14a shown in FIG. 5 can be formed. The
thickness thereof can be optionally adjusted by selecting the
length of processing time.
Subsequently, the switch S1 is opened, a switch S2 is closed after
transferring the insulating material 12 with the first underlayer
film 14a formed thereon to a position opposite the copper material
45 as the target material as shown by the phantom lines in FIG. 10
by use of a transfer means (not shown), and a DC voltage of around
-600 V supplied from a DC power source 43b is applied to the copper
material 45.
As a result, the sputtering process is applied to the copper
material 45, forming a copper film as the second underlayer film
14b over the first underlayer film 14a as shown in FIG. 5. The
thickness thereof can be optionally adjusted by selecting the
length of processing time.
Thereafter, the switch S2 is opened, a switch S3 is closed after
transferring the insulating material 12 with the first underlayer
film 14a and the second underlayer film 14b formed thereon to a
position opposite the silicon material 42 as the target material as
shown by the imaginary lines (on the extreme right side) in FIG. 10
by use of a transfer means (not shown), and a DC voltage of around
-600 V supplied from a DC power source 43c is applied to the
silicon material 42.
Thus, the sputtering process is applied to the silicon material 42
in the same way as for the preceding case, forming a silicon film
as the third underlayer film 14d over the second underlayer film
14c covering the insulating material 12, as shown in FIG. 5. The
thickness thereof can be optionally adjusted by selecting the
length of processing time, and the electrical resistance value of
the silicon film to be formed can also be controlled according to
the concentration of impurity contained therein by varying the
concentration of an impurity added to the silicon material 42 used
as the target material.
In the example shown in FIG. 10, the DC power sources 43a, 43b, 43c
are separately installed so that voltages applied to the titanium
material 44, copper material 45, and silicon material 42,
respectively, can be optimized. However, a DC common power source
may be adopted instead. In this case, the DC power source
preferably should be designed so as to be able to regulate an
output voltage as necessary.
The method of forming the hard carbon film 16 over the third
underlayer film 14d after the first, second, and third underlayer
films 14a, 14c, 14d are formed on the surface of the insulating
material 12 as shown in FIG. 5 is the plasma CVD process employing
the same system as described in the case of the embodiment
previously described with reference to FIG. 8, and explanation
thereof is therefore omitted.
Application Examples of the Invention: FIGS. 11 and 12
Now, application examples of the invention will be described with
reference to FIGS. 11 and 12.
FIG. 11 is a plan view of a transfer arm for semiconductor wafers,
to which the invention is applied, illustrating a state wherein a
semiconductor wafer is mounted thereon, and FIG. 12 a side view
thereof.
The transfer arm 60 has a notched portion 60c formed on the tip
thereof, and is provided with arm-like portions 60a, 60b, extended
on the opposite sides of the notched portion 60c, forming a
depression 60d for fitting a semiconductor wafer 70 therein on the
upper surface thereof.
By shifting the transfer arm 60 mounted on a transfer means (not
shown), the semiconductor wafer 70 fitted into the depression 60d
is transferred between processing steps.
The base member of the transfer arm 60 is composed of ceramic which
is an insulating material, the underlayer film according to one of
the embodiments of the invention described hereinbefore is formed
on the surface of the insulating material, and the hard carbon film
is further formed on the surface of the underlayer film.
Accordingly, there is neither any risk of the semiconductor wafer
being contaminated by the transfer arm, unlike the case of
employing a transfer arm made of a metal material alone, nor any
risk of the surface of the transfer arm generating fine particles
due to abrasion thereof caused by sliding contact with the
semiconductor wafer because the surface of the transfer arm coated
with the hard carbon film has very high wear resistance.
Furthermore, there is no risk at all of the surface of the transfer
arm being charged with static electricity, attracting dust in the
atmosphere, or destroying any integrated circuit formed on the
semiconductor wafer because of a reduction in the surface
electrical resistance of the hard carbon film down to the order of
10.sup.5 .OMEGA. due to the effect of the underlayer having
electric conductivity.
The invention is applicable to all of the various components, jigs,
and tools that have a base member composed of an insulating
material, and that are required to have a surface with very high
wear resistance and yet to have not-so-high surface electrical
resistance values. In particular, the method of the invention is
quite effective when applied to jigs and tools for handling
semiconductor wafers and chips described above.
As examples of the jigs and tools for handling the semiconductor
wafers and chips besides the transfer arm described above, there
can be cited a wafer cassette for holding a multitude of
semiconductor wafers, spaced apart from each other, while various
treatments are applied thereto, a wafer stage on which
semiconductor wafers are placed, a vacuum adsorber for transferring
semiconductor chips and the like by adsorbing the same, a pair of
tweezers for picking up and taking out the same, and the like.
The wafer stage is used for placing semiconductor wafers thereon
when applying a photo resist to the semiconductor wafers by use of
the spin coating method, applying an exposure treatment to the
photo resist by use of a photo mask, injecting impurity ions,
applying a dry etching process, or the like.
The invention may also be applied to guides of apparatuses and
components for handling semiconductor wafers and chips, which come
in sliding contact with the same.
The insulating material constituting the base member is not limited
to ceramic, and glass, plastics, or the like may be alternatively
used.
Effect of the Invention
As described in the foregoing, with the method of forming the films
over an insulating material according to the invention, the surface
hardness of the insulating material can be enhanced and the wear
resistance thereof can be dramatically improved by forming the hard
carbon film on the surface of the insulating material, while the
surface electrical resistance of the hard carbon film can be
controlled at a value lower than previously possible by forming the
underlayer films having electric conductivity, thereby preventing
the surface from being charged with static electricity with the
result that a risk of dust in the atmosphere being attracted by the
surface, or of articles coming in contact with the surface being
damaged, can be eliminated.
In particular, the invention, when applied to jigs and tools for
handling semiconductor wafers and chips, can ensure prevention of
an accident such as destruction of an integrated circuit formed on
the semiconductor wafers and chips caused by static electricity
with which the surfaces of the jigs and tools are charged.
* * * * *